Why do male characters make female noises?

Everytime I die as the Chief and my male Spartan IV: they sometimes make female noises? Is this some kind of bug for the audio or something?

> Everytime I die as the Chief and my male Spartan IV: they sometimes make female noises? Is this some kind of bug for the audio or something?

Master Chief screams like a girl when i die on Legendary but not on Heroic and under. Weird.